Lightning arrester



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BY MW MU dilarlze y LIGHTNING ARRESTER Filed Nov 25 1951 E. H. YONKERS, JR

Feb. 10, 1953 Patented Feb. 10,

LIGHTNING ARRESTER Edward H. Yonkers, In, Glencoe, Ill., assignor to Joslyn Mfg. & Supply 00., Chicago, 111., a. corporation of Illinois Application November 23, 1951, Serial No. 257,699 9 Claims. (01. 313-231) The present invention relates to lightning arresters, and more particularly to lightning arresters of the expulsion gap type, and the invention has for an object the provision of a lightning arrester of this type which is suitable for protecting encased electrical apparatus from voltage surges on conductors entering the apparatus and is characterized particularly by its simplicity of construction, low cost, and dependability of operation. Specifically, the present application constitutes a continuation-in-part of my copending application, Serial No. 177,487, filed August .3, 1950, which is assigned to the same assignee derstood by reference to the following specification taken in connection with the accompanying drawings, in which:

Fig. 1 is a sectional side elevational view of a lightning arrester unit constructed in accordance with the present invention;

Fig. 2 is an exploded view of the component parts of the lightning arrester unit shown in Fig. 1; and

Fig. 3 is a sectional side elevational view of an alternative embodiment of the lightning arrester of the present invention.

Referring now to the drawings, and more particularly to Figs. 1 and 2 thereof, the lightning .arrester unit of the present invention, which is indicated generally at [0, is illustrated in conjunction with the casing H of an enclosed electrical apparatus. In the illustrated embodiment the casing II comprises the bottom wall of a street lighting control unit of the type described and claimed in the copending application identified above. However, it will be understood that the lightning arrester unit of the present invention may be employed with any suitable encased electrical apparatus to provide. protection for the apparatus against voltage surges appearing on conductors incoming to the apparatus. The bottom wall ll of, the casing is provided with a plurality of apertures l2, l3, l4, and I5 through which apertures conductors extend to the interior of the control unit, and the bottom wall H is provided with a downturned flange l6 partially to enclose the lightning arrester units which are positioned within the apertures 12 to 15, inclusive, and surround the incoming conductors associated therewith.

The lightning arrester unit It, per se, comprises a hollow tubular rivet-like bushing or terminal member 20 which is preferably of copper and is provided with an outwardly extending flange portion 2| intermediate the length thereof. The flange 2i engages a steel washer 22 which is seated upon a terminal supporting and spacing member 23 of insulating material. The spacing member 23 is positioned upon the inner surface of the bottom wall ll of the casing and the members 22 and 23 are provided with apertures which are aligned with the aperture 12 in the wall H through which aligned apertures the hollow terminal member 20 extends. The terminal member 20 is hollow and is adapted to receive an incoming conductor such as the conductor 45 (Fig. 3) and one or more conductors 46 which are internal of the casing. The upper portion of the terminal member 20 may be crimped as illustrated at 41 to clamp the bare end portions 01 the conductors 45 and 46 within the terminal member 20 and provide electrical contact between these conductors.

The wall H is provided with a downwardly extending flange portion 25 adjacent the aperture l2 therein and there is provided a washer-like spacer 26 of insulating material which is positioned around the flange 25 concentrically therewith. An inverted cup-shaped metal electrode 28 is positioned below the insulating spacer 26 and is provided with a relatively large opening in the upper surface thereof to define a gap 29 between the inner edge 30 of the electrode 28 and the bottom edge of the flange 25. The upper surface of the cup-shaped electrode 28 is provided with radially extending corrugations 3! (Fig. 2) which define radially extending grooves or passageways 32 between the spacer 26 and the electrode 28. The passageways 32 serve as vent openings to permit the escape of gases produced in the above-described air gap 29 in a manner to be described in more detail hereinafter.

A bushing 35 of suitable insulating material such as porcelain or the like, is provided with a central bore 36 which is adapted to receive the terminal member 20, and is further provided with a shank portion 31 of reduced diameter which extends through the aligned apertures in the casing wall I I and the supporting member 23. The shank 3! thus functions to separate the conductive terminal from the flanged portion of the container wall II. A steel disl; electrode is positioned on the bottom end of the terminal member 20 adjacent the exposed end of the bushing 35 and is held in place by upsetting or spinning overthe end 4! of the bushing 29. The relative proportioning of the parts is such that the periphery of the disk electrode 49 is spaced from the rim portion of the cup-shaped electrode 28 to define an isolating air gap 42 between these members.

In order to extinguish an are which may be set up in the air gap 28 there is provided an insulating washer 52 which is positioned with n 4 ing gap to remove potential from the expulsion gap 2-9 to prevent carhonizing oi the insulating members in the vicinity of this gap. It will also be understood that the sparkover voltage or" the lightning arrester units is coordinated with the voltage ratings of the component elements with in the enclosed casing so that complete protection is obtained for all of the enclosed components even when direct lightning strokes are applied to the incoming conductors.

In the alternative embodiment shown in Fig.

-3, the expulsion gap 29 is lined on both sides the air gap 28 and is formed of a suitable gas I evolving or gas emitting material, such as methyl The washer s methacrylate, horn fibre, or the like. 59 acts as a spacer .to position the cup-shaped electrode .28 inconoentric relation to the shank of the bushing and thedisl: electrode i i-2i carried thereby.

it will be .evidentfroin .thezioregoing description that the lightning .arrester unit is rigidly secured to the casing wall I I due to the fact that the flange2l on the'terminalniember 26 and the spun over end portion thereof cooperate toclamp the component elements of the lightning arresterunitto'the sides of thecasing wall i I. It will further be evident .from the exploded-view of Fig; 2 that the componentlparts of the arrester unit may be quickly and easily assembled on the casing wallin the order shown therein to produce a complete arrester unit.

Considering now the operation or" he abovedescribed lightning 'arrester, when an over volt age occurs on a conductor extending through the central bore of thefterminalmeniber it, it will be evident from the foregoing description that a breakdown path for voltage surges appearing on thisconductor is established through the bottom end of theterminal-member Ed-and the.dlSkOltllIlBlElQCtTOdBfla 61162.11 gap ii, the cup-shaped electrode 128, and the-air gap 29 to the flanged edge125 of the casing wall 9 i. If the potential on the disk electrode 4% is "raised to the arrester sparkover voltage there will be an inn mediate discharge-from thiselectrode through the above-described breakdown path to the cating wall I I and if the casing is grounded the voltage surge will be conducted to ground. If the casing is ungrounded, as for example if the enclosedapparatus is supported on an insulating member, the voltagesurge will break down another lightning arrester unitassociated with the ground conductor so that the voltage surge is conveyed to ground without harming the encasedcomponents of the apparatus. When there is a 'discha'rge from the disk electrode through theisolating airgap 42 and through the cupshaped :electrode Z'tito the expulsion gs-p 29, the

heat of the arc evolves gases from the fiber washerfit positioned within the gap 2t which cool and de-ionize 'thearc stream and result in arc extinction at the first current zero. With this arrangement, continued arcing and-damage .from the (SO-cycle power follow current is prevented. The vent openings 32 which are provided in the ;cup:shape d electrode 28 permit the escape of the generated gases so that these vent openings actas are chutes to facilitate extinction of the arc. In this connection itwill be understood that the .a'irgap -42 acts. as isolah iti'onof gases from the heat of the are.

ing wall ii with horn fiber material to promote the produc- More specifically, there is provided in the alternative embodiment of Fig. 3 another insulating washer 52, whichisoi a gas evolving or gas emitting main and 52 so that arc extinguishing gases areimnedi'a-tely evolved when; an arc struck he tween'the cup-shaped electrode '23 and-the cas- In other respects the lightning arrester unit of Fig. 3 is identical tothe erohodl mentshown in detail in Figs. l and described heretoijore in connection therewith. A lightning arrester unit ,ofthe type shown in 3 has been tested on a --volt circuit having an available short circuit current of eoGdampere's. Under these conditions the operationofthe ligh ning arr-ester unit showed-that'the power are was extinguished in less than one-half of one current-cycle due toarc resistance.

-While there have been described :what areat present considered -;to :be the preferred embodiments of theinvention, fit willbeunderstoodithat various modifications may be made therein whichare within-the true spirit and scope ofthe invention as defined in :the appended claims.

What is claimed as new and desired to be secured by Letters Patent of the United States is:

1. A lightning'arrester unit for protecting. Jan encased electrical apparatus from voltage surges on' an incoming conductorthereof. comprising a conductive tubular member (extending through an aperture in the wall of [said casing and adapted to pass an incoming conductor therethrough, an insulating ibushing having .a head portion external'to said casing andai'shank portion extending through said aperture and having a central bore therethroughreceiving said tubular member, a disk electrode carried by said tubular member adjacent the head pcrtion of said bushing, a cupshapedelectrode-adapted to enclose the head portion of'said bushing and having a rimportion spaced from the periphery oi said disk electrode to form a iirstair gap therebetween, and an insulating spacer positioned between said casing" and the bottom edge of said cup-shaped electrode m rches a second air'gap therebetween.

'2 A lightning-arrester unit for protecting an encased electrical apparatus fronrvoltage Sur es on an incoming conductor "thereof, comprising a conductive tubular member extending through an aperture in the wall of said casing and adapted to passsan incoming conductor there through, an insulating bushing having a head portion'external ,to said casing" and a shank-portion extending through .said aperture and Lhavinga central bore theret-hrough receiving said tubular member, a conductivedisl; electrode-can ried by said tubular member adjacent the head portion of said bushing, a conductive cup-shaped electrode adapted to enclose the head portion of said bushing and having a rim portion spaced from the periphery of said disk electrode to form a first air gap therebetween, an insulating spacer positioned between said casing and the bottom edge of said cup-shaped electrode to provide a second air gap therebetween, and gas evolving means positioned within said second air gap.

3. A lightning arrester unit for protecting an encased electrical apparatus from voltage surges on an incoming conductor thereof, comprising a tubular conductive terminal member extending through an aperture in the wall of said casing and adapted to surround an incoming conductor, an insulating bushing having a head portion external to said casing and a shank portion extending through said aperture and having a central bore therethrough adapted to receive said tubular terminal member, a conductive disk electrode carried by said terminal member adjacent the head portion of said bushing, a cup-shaped conductive electrode adapted to enclose the head portion of said bushing and having a rim portion spaced from the periphery of said disk electrode to form a first air gap therebetween, an insulated spacer positioned between said casing and the bottom edge of said cup-shaped electrode to provide a second air gap therebetween, and gas evolving means positioned within said second air gap. a portion of the side wall of said terminal member internally of the casing being deformed inwardly to clamp a plurality of bare conductors therein and provide an electrical connection therebetween.

4. A lightning arrester unit for an apertured casing enclosing an electrical apparatus and having an outwardly extending flange portion surrounding the aperture thereof, comprising a conductive tubular member extending through said aperture and adapted to pass an incoming conductor therethrough, an insulating bushing having a head portion external to said casing and a shank portion extending through said aperture and having a central bore therethrough adapted to receive said tubular member, a conductive disk electrode carried by said tubular member adjacent the head portion oi said bushing, a, conductive cup-shaped electrode, concenitrio with said tubular member and opening outwardly to enclose the head portion of said bushing, said cup-shaped electrode having a rim portion spaced from the periphery of said disk electrode to form a first air gap therebetween and having an aperture in the bottom wall thereof adapted to receive the shank portion of said bushing therethrough, an insulating washer surrounding said fiange portion and positioned between said cup-shaped electrode and said casing to define a second air gap between the flanged portion of said casing and the inner edge of said cup-shaped electrode, and a washer of gas evolving material positioned within said second air ap, said cup-shaped electrode having radially extending grooves in the bottom surface thereof to provide vent openings communicating with 7 said second air gap.

5. A lightning arrester unit for an apertured casing enclosing an electrical apparatus and having an outwardly extending flange portion surrounding the aperture thereof, comprising a tubular conductive terminal member extending through said aperture and insulated from said casing and having an incoming conductor extending through the central bore thereof, a transverse conductive disk electrode carried by said terminal member externally of said casing, a cup-shaped conductive electrode concentric with said terminal member and opening outwardly from said casing, and means for spacing aid cup-shaped electrode between said casing and said disk electrode to define a pair of series connected air gaps between the incoming conductor and said casing.

6. A lightning arrester unit, comprising an apertured casing having an outwardly extending flange portion adjacent the aperture thereof, an insulating washer concentric with said aperture and surrounding said flange portion, a conductive sleeve concentric with said aperture and having an inwardly extending flange portion seated on said insulating spacer and spaced from said outwardly extending flange portion to define a first air gap therebetween, an elongated insulated bushing having an axial bore therethrough and a shoulder portion thereof adapted to engage said inwardly extending flange and arranged to protrude through said aperture into the interior of said casing, a conductive disk electrode positioned on said bushing and spaced from the rim portion of said conductive sleeve to define a second air gap therebetween, said inwardly extending flange portion having corrugations therein to define vent openings for said first air gap, and gas evolving means positioned within said first air gap.

7. A lightning arrester unit for protecting an encased electrical apparatus from voltage surges on an incoming conductor thereof, comprising a tubular conductive member extending through an aperture in the wall of said casing and adapted to pass an incoming conductor therethrough, an insulating bushing having a head portion external to said casing and a shank portion extending through said aperture and having a central bore therethrough receiving said tubular member, a conductive disk electrode carried by said tubular member adjacent the head portion of said bushing, a cup-shaped conductive electrode adapted to enclose the head portion of said bushing and having a rim portion spaced from the periphery of said disk electrode to form a first air gap therebetween, and means including a pair of washers of gas evolving material positioned between said casing and the bottom edge of said cup-shaped electrode for providing a lined expulsion gap therebetween.

8. A lightning arrest-er unit for protecting an encased electrical apparatus from voltage surges on an incoming conductor thereof, comprising a tubular conductive member extending through an aperture in the wall of said casing and adapted to pass an incoming conductor therethrough, an

insulating bushing having a head portion external to said casing and a shank portion extending through said aperture and having a central bore therethrough receiving said tubular member, a conductive disk electrode carried by said tubular member adjacent the head portion of said bushing, a cup-shaped conductive electrode adapted to enclose the head portion of said bushing and having a rim portion spaced from the periphery of said disk electrode to form a first air gap therebetween, an insulating spacer positioned between said casing and the bottom edge of said cupshaped electrode, and a pair of washers of gas evolving material positioned between said spacer and the head portion of said bushing and defining therebetween an expulsion gap between said cupshaped electrode and said casing.

9.. A lightning; an'estev-unitfob-protecting; an encased electrical? apparatus from voltage surges on an. incoming conductor thereof; comprisinggw tubular.conductive:m'emb'enextending through an aperture in th'ewall ofi said casing and adepted to pass. an incoming: conductor therethroughi an: insulating: bushing having-a. headportionexternal to said casing andva shank portion extending: through: said'aperture and having -a-centraliore therethrough receiving said tubulail membem a 1'0 conductive disk electrode-carriedbysaid tubular member adjacent 'the head portion of 'said' bush ing, acup-s-haped conductive-electrodeadaptedtoenclosethe-head portion of 'said bushing. andhaw mg a: rimportion spaced? from the: periphery: oi 1'5 said disk electrode to" forme-firstaiwgaip-mherebetween; van insulating;spacer-positioned between saidcasing and the-bottom edge of said cupshamed electrode, and a; pair of washers- 0f gas evolving material positioned-,-between* saidspa'c'er andthezhead portion of sa-idi bushinganddfihihg therebetiiveen a;--lined expulsion gap between 'said' cup-shaped electrode and said casing; the bottom of-sa-id" cup -shape'd-. electrode-being; corrugatedto provide: vent openings communioa bing-gwitn said expulsion gap; 1

YONKERS; J a;

Norreferen'ceszcitedli 

